I need to make application that will act as server and have clients. computers with client will get permission to go to internet or not via server. Only permission to go but they will connect directly on net (not a firewall). Its some sort of internet cafe management depending on time. Once time is out, server should send "sign" to client which will block the internet connection.
I want it to be un-terminable via task manager. So any ideas on where to start?